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Air Force Institute of Technology

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Articles 1921 - 1950 of 2678

Full-Text Articles in Physical Sciences and Mathematics

A Flexible Framework For Collaborative Visualization Applications Using Java Spaces, Sean C. Butler Mar 2001

A Flexible Framework For Collaborative Visualization Applications Using Java Spaces, Sean C. Butler

Theses and Dissertations

The complexity of modern tasks is rising along with the level of technology. Two techniques commonly used to deal with complexity are collaboration and information visualization. Recently, computer networks have arisen as a powerful means of collaboration, and many new technologies are being developed to better utilize them. Among the newer, more promising of these technologies is Sun Microsystems' JavaSpaces ™, a high-level network programming API. This thesis describes a tool for developing collaborative visualization software using JavaSpaces-an application framework and accompanying toolkit. In addition to a detailed description of the framework, the thesis also describes an application implemented using …

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Traveling Salesman Problem For Surveillance Mission Using Particle Swarm Optimization, Barry R. Secrest Mar 2001

Traveling Salesman Problem For Surveillance Mission Using Particle Swarm Optimization, Barry R. Secrest

Theses and Dissertations

The surveillance mission requires aircraft to fly from a starting point through defended terrain to targets and return to a safe destination (usually the starting point). The process of selecting such a flight path is known as the Mission Route Planning (MRP) Problem and is a three-dimensional, multi-criteria (fuel expenditure, time required, risk taken, priority targeting, goals met, etc.) path search. Planning aircraft routes involves an elaborate search through numerous possibilities, which can severely task the resources of the system being used to compute the routes. Operational systems can take up to a day to arrive at a solution due …

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Minimum Distance Estimation For Time Series Analysis With Little Data, Hakan Tekin Mar 2001

Minimum Distance Estimation For Time Series Analysis With Little Data, Hakan Tekin

Theses and Dissertations

Minimum distance estimate is a statistical parameter estimate technique that selects model parameters that minimize a good-of-fit statistic. Minimum distance estimation has been demonstrated better standard approaches, including maximum likelihood estimators and least squares, in estimating statistical distribution parameters with very small data sets. This research applies minimum distance estimation to the task of making time series predictions with very few historical observations. In a Monte Carlo analysis, we test a variety of distance measures and report the results based on many different criteria. Our analysis tests the robustness of the approach by testing its ability to make predictions when …

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Investigation Of Gravity Waves Via The Rotational Temperature Of Hydroxyl Nightglow, Erin C. Willingham Mar 2001

Investigation Of Gravity Waves Via The Rotational Temperature Of Hydroxyl Nightglow, Erin C. Willingham

Theses and Dissertations

Measurement of the vibration and rotation bands of mesospheric hydroxyl radicals (OH) has been conducted during the past two decades using ground-based and space-based interferometers to take temperature and wind measurements from 70-100km in altitude. Gravity waves that pass through the mesosphere can be measured by determining the variance over time of the rotational temperature of the OH emissions. Several attempts were made to take spectrum measurements of the nightglow from hydroxyl radicals in the mesosphere using a custom hardware configuration that included a telescope and grating monochrometer optimized for the visible and near infrared. Quantifying gravity wave activity was …

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A Model For Palladium Catalyzed Destruction Of Chlorinated Ethenes In Contaminated Groundwater, Christopher M. Stoppel Mar 2001

A Model For Palladium Catalyzed Destruction Of Chlorinated Ethenes In Contaminated Groundwater, Christopher M. Stoppel

Theses and Dissertations

Groundwater contamination by chlorinated ethenes is a widespread environmental problem. Conventional remediation technologies have shortcomings that have prompted further research into the development of novel treatment technologies. A palladium/ alumina catalyst in the presence of dissolved molecular hydrogen (referred to hereafter as a PD/H2 system) has been demonstrated to rapidly destroy chlorinated ethene contaminated groundwater. First-order kinetics have been used to model chlorinated ethene destruction in a PD/H2 reactor. However, catalyst deactivation and regeneration are important processes that also need to be modeled in order to better understand their effect on treatment efficiency. This study presents a model …

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Validation And Assessment Of Dmsp Electron Temperatures In The Topside Ionosphere, Bradford S. Green Mar 2001

Validation And Assessment Of Dmsp Electron Temperatures In The Topside Ionosphere, Bradford S. Green

Theses and Dissertations

Geomagnetic disturbances in the near earth space environment can adversely affect numerous military and Department of Defense (DoD) systems and operations. To improve the prediction accuracy of such disturbances, the next generation of space environment forecast models aims to automatically ingest real-time ionospheric measurements. This research validates and assesses one such measurement - the Defense Military Satellite Program (DMSP) measured electron temperature (Te). DMSP Te data were validated against near simultaneous incoherent scatter radar (ISR) Te measurements from Millstone Hill, MA and Sondrestrom, Greenland between Winter 1996 and Summer 2000. Of the 37 Millstone and six …

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Information Security: Securing Smart Cards With Iris Recognition, Orval E. Phelps Mar 2001

Information Security: Securing Smart Cards With Iris Recognition, Orval E. Phelps

Theses and Dissertations

This thesis examines the application of iris recognition technology to the problem of keeping smart cards secure. In order to understand the technology, a comprehensive literature review was conducted. The biological components of the iris were examined to ensure that they were truly random in development and static through the lifetime of the individual. Specifically, the physical structure of what comprises the iris was examined in detail. The data gathered indicates that the iris is formed early in development, random in structure, and stable throughout the person's lifetime. Next, the iris recognition process and resulting recognition code was examined to …

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Design And Specification Of Dynamic, Mobile And Reconfigurable Multiagent Systems, Athie L. Self Mar 2001

Design And Specification Of Dynamic, Mobile And Reconfigurable Multiagent Systems, Athie L. Self

Theses and Dissertations

Multiagent Systems use the power of collaborative software agents to solve complex distributed problems. There are many Agent-Oriented Software Engineering (AOSE) methodologies available to assist system designers to create multiagent systems. However, none of these methodologies can specify agents with dynamic properties such as cloning, mobility or agent instantiation. This thesis starts the process to bridge the gap between AOSE methodologies and dynamic agent platforms by incorporating mobility into the current Multiagent Systems Engineering (MaSE) methodology. Mobility was specified within all components composing a mobile agent class. An agent component was also created that integrated the behavior of the components …

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Implementation And Analysis Of The Parallel Genetic Rule And Classifier Construction Environment, David M. Strong Mar 2001

Implementation And Analysis Of The Parallel Genetic Rule And Classifier Construction Environment, David M. Strong

Theses and Dissertations

This paper discusses the Genetic Rule and Classifier Construction Environment (GRaCCE), which is an alternative to existing decision rule induction (DRI) algorithms. GRaCCE is a multi-phase algorithm which uses evolutionary search to mine classification rules from data. The current implementation uses a genetic algorithm based 0/1 search to reduce the number of features to a minimal set of features that make the most significant contributions to the classification of the input data set. This feature selection increases the efficiency of the rule induction algorithm that follows. However, feature selection is shown to account for more than 98 percent of the …

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Incoherent Beam Combining Using Stimulated Brillouin Scattering In Multimode Fibers, Timothy H. Russell, Won B. Roh, John R. Marciante Feb 2001

Incoherent Beam Combining Using Stimulated Brillouin Scattering In Multimode Fibers, Timothy H. Russell, Won B. Roh, John R. Marciante

Faculty Publications

A beam combining technique for producing a single, spatially coherent beam from two mutually incoherent (temporally and spatially) lasers is demonstrated and the spatial coherence properties of the resulting beam are characterized. The technique is based on simultaneous excitation of stimulated Brillouin scattering by two independent lasers operating at two different wavelengths in a long multimode optical fiber. Though spectrally independent, the resulting Stokes beams produce essentially identical intensity distributions corresponding to the fundamental fiber mode. Abstract © 2001 Optical Society of America.

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Computer-Based Methods For Constructing Two-Level Fractional-Factorial Experimental Designs With A Requirement Set, Steven L. Forsythe Dec 2000

Computer-Based Methods For Constructing Two-Level Fractional-Factorial Experimental Designs With A Requirement Set, Steven L. Forsythe

Theses and Dissertations

This dissertation developed four methodologies for computer-aided experimental design of two-level fractional factorial designs with requirement sets (DOE/RS). The requirement sets identify all the experimental factors and the appropriate interaction terms to be evaluated in the experiment. Taguchi graphs and similar manual methods provide techniques for solving the DOE/RS problem. Unfortunately, these methods are limited because they become difficult to use as the number of factors or interaction terms exceeds ten. This research showed that the DOE/RS problem belongs to a class of difficult-to-solve problems known as NP-Complete. It is the combinatorial nature of NP-Complete problems that causes them to …

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Validation And Verification Of Formal Specifications In Object-Oriented Software Engineering, Steven A. Thomson Sep 2000

Validation And Verification Of Formal Specifications In Object-Oriented Software Engineering, Steven A. Thomson

Theses and Dissertations

The use of formal specifications allows for a software system to be defined with stringent mathematical semantics and syntax via such tools as propositional calculus and set theory. There are many perceived benefits garnered from formal specifications, such as a thorough and in-depth understanding of the domain and system being specified and a reduction in user requirement ambiguity. Probably the greatest benefit of formal specifications, and that which is least capitalized upon, is that mathematical proof procedures can be used to test and prove internal consistency and syntactic correctness in an effort to ensure comprehensive validation and verification (V&V). The …

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Algorithm Development For On-Line Control Of The Airborne Laser, Michael W. Oppenheimer Sep 2000

Algorithm Development For On-Line Control Of The Airborne Laser, Michael W. Oppenheimer

Theses and Dissertations

The use of adaptive optics entails the design of a controller. This requires the development of a model of the plant to be controlled, which, in this case, Consists of the atmosphere through which light is traveling. In optics, Zemike polynornials are used as a basis set for the expansion of wavefront phase distortions. Due to the turbulence induced stochastic nature of the underlying process involved, the spatial-temporal correlation functions of the Zemike polynomial phase expansion coefficients must be evaluated if a proper stochastic model of the plant is to be developed and adaptive optics is to be employed. In …

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An Improved Algorithm For Translating Relational Schemas Into An Object Model, Joseph C. Pearson Jun 2000

An Improved Algorithm For Translating Relational Schemas Into An Object Model, Joseph C. Pearson

Theses and Dissertations

Today's war fighter is inundated with data from numerous Command, Control, Communications and Computers and Intelligence systems. Integration of these systems is desirable, yet integration results in a static solution to a dynamic problem-by the time a global schema can be devised, it is out of date. Automating schema integration will mitigate this problem, but data model disparity must be addressed via translation to a common data model prior to integration. To address this requirement, this thesis presents an improved, relational to object-oriented schema translation algorithm, which is derived from a base algorithm proposed by another research effort. The improved …

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An Analysis Of The Effectiveness Of A Constructive Induction-Based Virus Detection Prototype, Kevin T. Damp Apr 2000

An Analysis Of The Effectiveness Of A Constructive Induction-Based Virus Detection Prototype, Kevin T. Damp

Theses and Dissertations

Computer viruses remain a tangible threat to systems both within the Department of Defense and throughout the greater international data communications infrastructure on which the DoD increasingly depends. This threat is exacerbated continually, as new viruses are introduced at an alarming rate by the growing collection of connected machines and their operators. Unfortunately, current antivirus solutions are ill-equipped to address these issues in the long term. This thesis documents an investigation into the use of constructive induction, a form of machine learning, as a supplemental antivirus technique theoretically capable of detecting previously unknown viruses through generalized decision-making techniques. A group …

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A Comparative Analysis Of Proposed Mobility Support Schemes For Ip Multicast, Alexander Muller Jr. Apr 2000

A Comparative Analysis Of Proposed Mobility Support Schemes For Ip Multicast, Alexander Muller Jr.

Theses and Dissertations

This thesis introduces a novel mobile multicast transmission mechanism called Minimal Multicast Encapsulation. Additionally, this thesis analyzes the performance of mobility support schemes for IP multicast. Specifically, it compares the performance of combinations of two receive mechanisms and two transmit mechanisms. The receive mechanisms are the Internet Engineering Task Force (IETF) bi-directional tunneling mechanism and the IETF remote subscription mechanism. The transmit mechanisms are the IETF home tunneling mechanism and the Minimal Multicast Encapsulation. The performance analysis consists of examining path efficiencies, packet loss rates, and required mobility agent throughputs for each of the four possible combinations of the aforementioned …

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Validation Of The Ionospheric Forecast Model (Ifm) Version 3, Michael D. Scott Mar 2000

Validation Of The Ionospheric Forecast Model (Ifm) Version 3, Michael D. Scott

Theses and Dissertations

The purpose of this research was to validate the Ionospheric Forecast Model (IFM) Version 3 to assess its suitability and usefulness as an operational tool. The Ionospheric forecast model is a first principles computer model designed to forecast the state of the global ionosphere to 24 hours. The scope was limited to a comparison of the F2 layer critical frequency (foF2) and peak electron density (hmF2) against observed ionosonde data. The model was run with global solar and geomagnetic indices and Information from Digitial Ionospheric Sounding System (DISS) observations as inputs. The DISS observations were input through the Parameterized Real-Time …

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An Analysis In Cloud-To-Ground Lightning Over Land Versus Water, Elizabeth A. Boll Mar 2000

An Analysis In Cloud-To-Ground Lightning Over Land Versus Water, Elizabeth A. Boll

Theses and Dissertations

Understanding lightning characteristics over land and water is vital to achieving optimal safety and success in Air Force missions. Lightning safety rules are often based on experience rather than a scientific understanding of lightning. Examining lightning characteristics over water and land will assist in a better understanding of lightning and provide answers that can protect human lives and property. Water and land have different compositions and surface conductivity values. A lightning stroke is detected through a change in the electro-magnetic field at the surface. The change in surface conductivity values from land to water can affect the detection of a …

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A Neural Network Solution To Predicting Wind Speed At Cape Canaveral’S Atlas Launch Pad, Kenneth P. Cloys Mar 2000

A Neural Network Solution To Predicting Wind Speed At Cape Canaveral’S Atlas Launch Pad, Kenneth P. Cloys

Theses and Dissertations

This thesis demonstrates the potential for using time-delay neural networks to provide Launch Weather Officers (LWOs) at 45th Weather Squadron (45 WS) with advance warning of wintertime (November-March) peak wind speeds at the Atlas launch pad. The 45 WS provides weather support to the United States space program at Cape Canaveral Air Station, NASA's Kennedy Space Center, and Patrick Air Force Base. Due to the complex wintertime environment produced by the effects of friction and instability, 45 WS LWOs consider wintertime launch pad winds their toughest forecast challenge. Neural networks were developed, trained, and tested using observations of wintertime peak …

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Multi-Conjugate Adaptive Optics For The Compensation Of Amplitude And Phase Distortions, Peter N. Crabtree Mar 2000

Multi-Conjugate Adaptive Optics For The Compensation Of Amplitude And Phase Distortions, Peter N. Crabtree

Theses and Dissertations

Two deformable mirrors (DMs) with finite conjugate ranges are investigated for compensating amplitude and phase distortions due to laser propagation through turbulent atmospheres. Simulations are performed based on Adaptive Optics (AO) for an Airborne Laser-type scenario. The Strehl ratio, the number of branch points in DM controls, and the number of iterations to convergence are used as figures of merit to evaluate performance of the Sequential Generalized Projection Algorithm that generates mirror commands. The results are ensemble averages over 32 realizations of the scintillated test fields for each value of the Rytov parameter within the test scenario. The Gaussian beam …

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In Situ Treatment Of Chlorinated Ethene-Contaminated Groundwater Using Horizontal Flow Treatment Wells, Derek R. Ferland Mar 2000

In Situ Treatment Of Chlorinated Ethene-Contaminated Groundwater Using Horizontal Flow Treatment Wells, Derek R. Ferland

Theses and Dissertations

The limitations of conventional containment technologies for groundwater contaminated with chlorinated solvents have motivated development of innovative technologies to achieve national groundwater remediation objectives. One inn9vative technology that is currently under development involves metal reductants or catalysts to chemically destroy the dissolved chlorinated solvent. Models are important tools that can be used to help transition this technology to the field. Model studies can be used to gain understanding about the technology, help determine when the prospective technology might work for a given site, and design full-scale field applications.

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Temperature Determination In An I2 Gas Using Dopper-Limited Saturation Spectroscopy, James W. Myers Jr. Mar 2000

Temperature Determination In An I2 Gas Using Dopper-Limited Saturation Spectroscopy, James W. Myers Jr.

Theses and Dissertations

Saturation spectroscopy techniques were used to demonstrate the ability to make spatially resolved temperature measurements by exploiting the B3 ∏(O+u) - X1 Σ ;(O+g) electronic transition in molecular iodine (I2). Doppler-free saturation spectroscopy measurements resulted in hyperfine spectral profiles for the P(7O) 17-1 and P(53) 19-2 ro-vibrational transitions between the electronic levels. Doppler-limited saturation spectroscopy, an adaptation of the Doppler-free technique in which beams propagate in the same direction and cross within the gas sample, allowed for the measurement of spatially resolved Doppler profiles for the same transitions. The profiles were measured …

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A Study Of Morning Radiation Fog Formation, Jimmie L. Trigg Jr. Mar 2000

A Study Of Morning Radiation Fog Formation, Jimmie L. Trigg Jr.

Theses and Dissertations

This research focuses on developing a linear regression formula that forecasters in the Midwest can use to accurately anticipate the formation of radiation fog. This was accomplished in three stages. First a study of the surface and upper air parameters and processes required to develop radiation fog were identified and explored. Next, a linear regression technique was applied to the 23 parameters identified. The top four indicators were then reprocessed and a new linear regression equation was developed. Finally, the new regression equation was compared to an existing fog forecasting technique. The existing forecast technique selected was the 2nd Weather …

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Determining The Horizontal Distance Distribution Of Cloud-To-Ground Lightning, Tamara L. Parsons Mar 2000

Determining The Horizontal Distance Distribution Of Cloud-To-Ground Lightning, Tamara L. Parsons

Theses and Dissertations

This research effort attempted to quantify what constitutes a safe distance when lightning is present. The method used in this research project groups lightning flashes into clusters using spatial and temporal constraints. However, not all flashes meet the time and distance criteria for clustering and remained outside of tile grouped flashes and as such are identified as isolated flashes. These isolated flashes are outliers in the data set, but are precisely the flashes that prove most dangerous. For this reason not only were the distances between each flash and cluster center studied, but also the distances between each isolated flash …

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Investigation Of Laser Beam Combining And Cleanup Via Seeded Stimulated Brillouin Scattering In Multimode Optical Fibers, Bryan J. Choi Mar 2000

Investigation Of Laser Beam Combining And Cleanup Via Seeded Stimulated Brillouin Scattering In Multimode Optical Fibers, Bryan J. Choi

Theses and Dissertations

The purpose of this thesis research was to determine if stimulated Brillouin scattering amplification in multimode optical fibers would exhibit the same laser beam combining and clean-up properties exhibited by SBS oscillation, and to characterize the Brillouin amplification process in a multimode optical fiber. Beam combining in multimode fibers via SBS is being considered as a method of combining low power laser beams into a single beam having higher power and superior spatial coherence for applications such as electro-optic countermeasures. Experimental results demonstrate seeding a 9.5 mm fiber significantly reduced the pump power required to initiate SBS. An amplified Stokes …

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An Evaluation Of Microburst Prediction Indices For The Kennedy Space Center And Cape Canaveral Air Station (Ksc/Ccas), Steven N. Dickerson Mar 2000

An Evaluation Of Microburst Prediction Indices For The Kennedy Space Center And Cape Canaveral Air Station (Ksc/Ccas), Steven N. Dickerson

Theses and Dissertations

A wet-microburst event on 16 August 1994 at the Kennedy Space Center's Shuttle Landing Facility alerted forecasters from the 45th Weather Squadron (45WS), the provider of weather support to the Kennedy Space Center (KSC) and Cape Canaveral Air Station (CCAS), to the challenges of wet-microburst prediction. Although there was no operational impact, this event caused the 45WS to revise their severe thunderstorm forecasting procedures to specifically address microbursts, resulting in the locally developed Microburst-Day Potential Index (MDPI). MDPI provides a several-hour outlook of microburst potential based on the results of the Microburst and Severe Thunderstorm (MIST) project. The 45WS also …

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Atmospheric Temperature Profiles By Ground-Based Infrared Spectrometer Measurements, Jon M. Saul Mar 2000

Atmospheric Temperature Profiles By Ground-Based Infrared Spectrometer Measurements, Jon M. Saul

Theses and Dissertations

A method to recover atmospheric temperature profiles using a ground-based Fourier Transform Infrared spectrometer was investigated. The method used a difference form of the radiative transfer equation, a Bomem MR series Fourier Transform Infrared Spectrometer to collect atmospheric radiance values, and the Phillips Laboratory Expert- assisted User Software (PLEXUS) atmospheric radiance model, to recover an atmospheric temperature profile. The method researched uses radiance values from both the spectrometer measurements and the atmospheric model, along with kernel functions calculated by the atmospheric model as input to a difference form of the radiation transfer equation. From this the change in brightness temperatures …

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Improving The Analyst And Decision-Maker’S Perspective Through Uncertainty Visualization, Evan T. Watkins Mar 2000

Improving The Analyst And Decision-Maker’S Perspective Through Uncertainty Visualization, Evan T. Watkins

Theses and Dissertations

This thesis constructs the Taxonomy of Uncertainty and an approach for enhancing the information in decision support systems. The hierarchical categorization of numerous causes for uncertainty defines the taxonomy, which fostered the development of a technique for visualizing uncertainty. This technique is fundamental to expressing the multi-dimensional uncertainty that can be associated with any object. By including and intuitively expressing uncertainty, the approach facilitates and enhances intuition and decision-making without undue information overload. The resulting approach for enhancing the information involves recording uncertainty, identifying the relevant items, computing and visualizing uncertainty, and providing interaction with the selection of uncertainty. A …

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Data Warehouse Techniques To Support Global On-Demand Weather Forecast Metrics, Meriellen C. Joga Mar 2000

Data Warehouse Techniques To Support Global On-Demand Weather Forecast Metrics, Meriellen C. Joga

Theses and Dissertations

Air Force pilots and other operators make crucial mission planning decisions based on weather forecasts; therefore, the ability to forecast the weather accurately is a critical issue to Air Force Weather (AFW) and its customers. The goal of this research is to provide Air Force Weather with a methodology to automate statistical data analysis for the purpose of providing on-demand metrics. A data warehousing methodology is developed and applied to the weather metrics problem in order to present an option that will facilitate on-demand metrics. On-line analytical processing (OLAP) and data mining solutions are also discussed.

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Analysis Of The Air Force Iso 14001 Pilot Study Conducted By Dod, Rodney C. Harris Mar 2000

Analysis Of The Air Force Iso 14001 Pilot Study Conducted By Dod, Rodney C. Harris

Theses and Dissertations

The Department of Defense (DoD) conducted an ISO 14001 pilot study with the primary goal of determining how ISO 14001 could help DoD organizations reduce risks, improve compliance with environmental regulations, enhance stewardship, contain costs, and meet emerging regulatory requirements. This thesis analyzed the pilot study, specifically looking at the ISO 14001 implementation at three Air Force installations participating in the study. The research objectives were to identify factors that affect implementation of ISO 14001, compare the implementation strategies used by the bases, and develop propositions for Air Force managers to consider when implementing ISO 14001. Interviews of key personnel, …

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